1. Field of the Invention
This invention relates to coaxial cable connectors.
2. Introduction to the Invention
A connector commonly used in coaxial cable systems is known as the F-connector. The F-connector is typically found on cables and devices from a cable tap at a distribution cable to equipment at a subscriber's premises. A male F-connector is typically used to terminate a coaxial cable. An F-connector having a female F-port may be used to connect a coaxial cable to a device, e.g. to a cable tap, splitter, etc. An F-connector having two female ports may be used to join two coaxial cables together. Because F-connectors are used in such large quantities, it has been necessary to develop F-connectors which are easily assembled and inexpensive. As used herein, the terms female connector, female F-port and F-port are considered synonymous.
A wire connecting the distribution cable to a subscriber's premises is commonly referred to as a dropwire. The dropwire is typically terminated with male F-connectors at both ends and connects to a female F-port at the cable tap and a female F-port at the subscriber's premises. In residential installations, it is common for the dropwire to connect to an F-port on a ground block which may be mounted to an outside wall of the subscriber's residence. Additional F-ports and male F-connectors may also be employed, e.g., with splitters, wall plates, and other devices, and associated cabling used to condition and distribute the cable signals to equipment located within the subscriber's premises.
The connections between the cable tap F-ports and the dropwire F-connectors, as well as connectors on other cabling and equipment situated outside, are all subject to attack from the elements, particularly ingress by moisture from rain and conditions of high relative humidity. In areas where this has posed a problem, attempts have been made to seal such connections. One means of sealing employs an elastic sealing sleeve which is first slipped over the end of the cable, and then, after the connectors are joined, the sleeve is repositioned over the connectors. Another means employs a ring-shaped compression gasket which fits around the female connector, and, upon screwing the male connector shell on the female connector, the compression washer forms a seal between the leading edge of the connector shell and an opposing face of the female connector. However, such compression washers can turn with the connector shell as the connector shell is screwed on, and provide a leak path through the center hole in the washer, between the washer and the outer surface of the connector. These approaches have provided some measure of protection for connections used in cable systems to date. However, they only provide a very modest sealing capability, and, in particular, do not adequately seal the threaded sections of the mating connectors. Moreover, with distribution cables and cable taps typically carried high above ground, it can be cumbersome for the craft person to install such sealing devices.
In another approach, a sealant element is contained within the connector shell. The sealant element deforms when the connector shell is screwed onto the threaded female connector. However, connector shells made by different manufacturers vary in certain dimensions, particularly with respect to the depth of the connector shell and the number of threads. Thus the effectiveness of the sealant may vary depending on the compatibility of the female connector with the connector shell on the male connector, and whether the craft person adequately tightens the connector shell on the female connector. In another approach, the sealant element may be a cylindrical sleeve which is compressed between the mating threads of the two connectors. However, such sleeves can require replacement upon reentry, which may also be a cumbersome task for the craft person.
It is also known to apply a liquid or strand-like sealing material to one or both of the threads of the mating parts prior to screwing on the connector shell. However, the integrity of the resulting seal is dependent upon the care with which the sealing material is applied, and is often neglected by craft persons under stressful or poor climate conditions.
With higher bandwidth and digital signals being introduced, and with cable systems beginning to carry power to the subscriber, there is a need in the cable television industry to provide an effective means of sealing coaxial cable connectors to resist signal degradation. There is likewise a need to provide a means of sealing such connectors which means is not cumbersome or dependent on the skill of the craft person. There is also a need to provide such a sealing means which is integral to the coaxial cable connectors to simplify the installation of the sealing means.